1. Technical Field
An aspect of the present invention relates to a bearing device, a drum unit, and an image forming apparatus.
2. Related Art
A tandem-typed image forming apparatus having an image forming unit to form an image on a recording medium in, for example, an electrophotographic method is known. The image forming apparatus may be equipped with a plurality of photosensitive drums, each of which is capable of forming an image in a different color, are arranged in line. For example, a tandem-typed color printer having four photosensitive drums, which are integrally attachable in and detachable from a casing of a body of the printer, is known.
Such a printer may be equipped with drum subunits to support the photosensitive drums respectively and a pair of side frames to hold the drum subunits at axial end portions thereof. The side frames are configured to further hold detachable developer cartridges, each of which includes a developer roller corresponding to one of the drum subunits. Thus, the drum subunits, the developer cartridges, and the pair of side frames consist of a drum unit to be detachably installed the casing of the printer.
A structure to hold the photosensitive drums by the pair of side frames may be, for example, such that each photosensitive drum is provided with flanges at axial end portions thereof, and the flanges are rotatably inserted in bearings, which are fixed to through holes formed in the side frames. Thus, the flanges are rotatable with respect to the bearings and the side frames.